Commitments and Contigencies (Details Textual) - USD ($)	Sep. 30, 2017	Oct. 02, 2014
Business Acquisition [Line Items]
Percentage of labor force covered by collective bargaining agreements	11.00%
Palmarejo gold production royalty [Member]
Business Acquisition [Line Items]
Production to be sold, percent		50.00%
Price per ounce under agreement		$ 800
Aggregate deposit to be received		$ 22,000,000